Axial flow compressor



Nov. 25, 1952 F. SCHAER 2,619,279

4 AXIAL FLOW COMPRESSOR Filed June 22, 1949 5 Sheets-Sheet 1 IN V ENTOR.-

SCHAER NOV. 25, 1952 SCHAER 2,619,279

AXIAL. FLOW COMPRESSOR Filed June 22, 1949 3 Sheets-Sheet 2 MIL IN VENTOR.- FRANZ SCH/35R Nov. 25, 1952 F. SCHAER AXIAL mow COMPRESSOR 3Sheets-Sheet 3 Filed June 22, 1949 w T m. V N I FRANZ SCHAER BY M. A

ATTORNE Paiented Nov. 25, 1952 AXIAL FLOW COMPRESSOR Franz Schaer,Winterthur, Switzerland, assignor to Sulzer Freres, Socit Anonyme,Winterthur, Switzerland, a corporation of Switzerland Application June22, 1949, Serial No. 100,700 In Switzerland July 16, 1948 1 Claims.

The present invention relates to multistage axial flow compressorshaving at least one cooler for the compressed medium.

It is an object of the invention to arrange in the casing of an axialflow compressor a cooler for the compressed medium in such a manner thatthe temperature of the outer portions of the casing is approximately thesame as that of the inner portions whereby heat stresses anddeformations are avoided, and that the inlet and outlet channels of onegroup of compressor stages can be arranged adjacent to one anotherwithout undue heat exchange through the wall portions of the casingseparating said channels.

An object of the present invention resides in the combination of thecasing of an axial flow compressor with an intercooler in such a mannerthat the medium flowing in axial direction through a group of compressorstages passes the intercooler in axial direction substantially oppositeto the direction in which the medium has passed through the compressorand that the compressed and cooled medium flows in pressure conduitswhich are adjacent to the suction conduits of said group of stages ofthe compressor.

A further object of the invention resides in the provision of acompressor having two axially arranged groups of stages in one casing,the medium flowing in opposite directions through said groups and theinlet conduit or conduits of one group being adjacent to its outletconduits and the latter forming the inlet conduit or conduits of theother group of stages. In this way the axial thrusts of the rotors ofthe two groups balance one another without necessitating complicatedfiow and conduits for the medium. A further beneficial result of thearrangement according to the invention is the elimination of heatexpansion of the casing in the middle of the compressor unit and thefact that the unit may be supported rigidly thereat, i. e. at its centerof gravity, and its inlet can be rigidly connected with the mediumsupply conduit without special provisions for expansion.

A further object of the invention is the provision of a compressorhaving two axially arranged groups of stages and a cooler for thecompressed medium provided for each group, the medium flowing througheach cooler in a direction opposite to that in which it flows throughthe group of compressor stages to which the cooler belongs; the suctionconduit of the first group of stages being in the neighborhood of theoutlet of the cooler of the second group, which is the outlet of thewhole compressor unit. ,Since the highly compressed medium is cooled inthe second cooler and the outlet thereof is in the neighborhood of theinlet of the compressor unit, not only the inlet but also the outlet ofthe unit can be rigidly fitted to the connecting ducts without specialprovisions for taking care of expansion. In the described arrangement,temperature expansion in the middle of the unit where its center ofgravity is located, is avoided and the unit may be rigidly supported atits center portion and connected with the suction and pressure ducts,Whereas the hot end portions of the unit which may be slidinglysupported or be not supported at all, can expand freely.

Further and other objects of the present invention will be hereinafterset forth in the accompanying specification and claims and shown in thedrawings, which by way of illustration show what I now consider to bepreferred embodiments of the invention.

In the drawings:

Fig. l is a horizontal longitudinal sectional view of a compressoraccording to the invention;

Fig. 2 is a vertical sectional view of the compressor illustrated inFig. 1;

Fig. 3 is a cross-sectional View of the compressor shown in Figs. 1 and2, and taken along lines II of said figures;

Fig. l is a cross-sectional view of the compressor shown in Figs. 1 and2, and taken along lines II--II of said figures;

Fig. 5 is a horizontal longitudinal sectional view of a modifiedcompressor according to the invention;

Fig. 6 is a vertical longitudinal sectional view of the compressorillustrated in Fig. 5;

Fig. '7 is a cross-sectional view of the compressor shown in Figs. 5 and6, and taken along lines III-III of said figures;

Fig. 8 is a cross-sectional view of the compressor shown in Figs. 5 and6, and taken'along lines IV-IV of said figures;

Fig. 9 is a cross-sectional view of the compressor shown in Figs. 5 and6, and taken along lines VIVI of said figures;

Figure 10 is a longitudinal vertical sectional view of a part of themodified compressor according to the invention, the section being takenalong lines VV in Figs..5, 7, and 9.

Like parts are designated by like numerals in all figures of thedrawings.

Referring more particularly to Figs. 1 to 4 of the drawings, numerals land I designate the two aligned rotors of the compressor unit havingblades 3 and 3', respectively, and numerals 2, 2 the associated statorshaving buckets 4 and 4, respectively, only the blades and buckets at theends of the two groups of compressor stages being shown to avoidoverloading of the drawing.

The first group of stages receives medium to be compressed from theinlet conduit 5 through the suction channel 6 and compresses it in thedirection indicated by arrow 1. The compressed and thereby heated mediumis discharged into the annular channel 8 wherein its flow direction isreversed, and flows through a cooler 9 in a direction opposite to thatof arrow 1. The cooler is built into the casing and comprises a coolingcoil or other heat transfer means which are not shown as they do notform part of thepresent invention. The cooled medium is conductedthrough the pressure conduits It! to the second group of compressorstages. The medium in channels H] has approximately the same temperatureas the medium flowing through suction conduits 6 and no heat transferoccurs through the separating walls H, which would reduce the efiiciencyof the machine. The compressed medium is available in about the sameradial plane, for withdrawal or for further compression, in which it wasintroduced into the compressor whereby the construction of the unit isconsiderably simplified. A further advantage is that the medium whosetemperature increased from the inlet 6 in the direction of arrow 1, iscooled to approximately its original temperature while passing through8, 9 and ID in about the same sequence. The temperatures near thediametrical center of the unit are therefore approximately equal tothose on the periphery whereby tension in radial direction anddeformations due to heat are avoided.

Compressed and cooled medium may be withdrawn from the channels Ii]preferably at the radial plane in which the suction conduit 5 islocated. The rest of the medium or, in the embodiments illustrated, allof it is further compressed in a second group of compressor stages whichis arranged coaxially with the first group and which receives thepre-compressed medium from the channels I which are disposed adjacent tothe suction channels 6. The medium flows through stages 2 in thedirection of arrow [2 which is opposite to that in which the mediumflows through stages 2. The medium compressed and thereby heated in thesecond group of compressor stages passes therefrom into the annularchamber l3 from which it is conducted to the compressor outlet M.

An arrangement according to Figs. 1 to 4 is used if heating of themedium in the second part of the compressor is not objectionable or isdesired.

If the compressed medium is required at a low temperature, for exampleif it must be further compressed, the arrangement according to theinvention may be modified as shown in Figs. to 10. In this case thedirection of flow of the medium leaving the second part of thecompressor is reversed in the annular conduit 13', directed through acooler M in a direction opposite to that of arrow 12, enters thepressure channels IS in cooled condition, and leaves the compressorthrough outlet [6. The temperature of the medium in conduits 6, i0 andi5 is approximately the same and these conduits can be arranged closelyto one another without reducing the efficiency of the unit. For the same4 reason, the outlet Hi can be in the same radial plane of thecompressor as the inlet 5.

Chambers H of the compressor casing which are not used for conductingthe medium to be compressed, may be provided with separating walls l8for preventing generation of convection currents in the chambers.

While I believe the above described embodiments of my invention to bepreferred embodiments, I wish it to be understood that I do not desireto be limited to the exact details of method, design and constructionshown and described, for obvious modifications will occur to a personskilled in the art.

I claim:

1. An axial flow compressor comprising a casing, a longitudinal rotordisposed in said casing, blades extending substantially radially fromsaid rotor, buckets extending substantially radially from said casingand between said blades; a suction conduit in said casing for conductingthe medium to be compressed to one end of said rotor; a cooler disposedin said casing and around said rotor between its ends; a medium fiowreversing outlet conduit in said casing at the other end of said rotor,reversing the direction of flow of the medium and being connected withsaid cooler for conducting the medium thereinto and therethrough in adirection substantially opposite to that in which it flows through therotor; and an outlet conduit in said casing connected with said coolerfor receiving the compressed and cooled medium from said cooler, saidpressure conduit being adjacent to said suction conduit.

2. An axial flow compressor comprising a casing, a longitudinal rotordisposed in said casing, blades extending substantially radially fromsaid rotor, buckets extending substantially radially from said casingand between said blades; a suction conduit in said casing for conductingthe medium to be compressed to one end of said rotor; a cooler disposedin said casing and around said rotor between its ends; a medium flowreversing outlet conduit in said casing at the other end of said rotor,reversing the direction of flow of the medium and being connected withsaid cooler; a pressure conduit in said casing receiving the compressedand cooled medium from said cooler, said pressure conduit neighboringsaid suction conduit; a second longitudinal rotor disposed in saidcasing coaxially with and having an end proximal to the first rotor,blades on said second rotor, buckets connected with said casing andextending between the blades of said second rotor, an intake at theproximal end of said second rotor and connected with said pressureconduit for receiving precompressed and cooled medium from the coolerand conducting it into the second rotor to fiow therethrough in adirection opposite to that in which it flows through the first rotor,and a medium discharge conduit in said casing at the end of the secondrotor which is distal to the first rotor.

3. An axial flow compressor as defined in claim 2, having a secondcooler disposed in said casing around said second rotor, the dischargeconduit of the second rotor being connected with said second cooler andso shaped as to reverse the flow of the medium and to direct it into andthrough the second cooler in a direction substantially opposite to thatin which it flows through the second rotor, and a second pressureconduit in said casing connecting with and receiving the medium fromsaid second cooler and disposed in the neighborhood of said suctionconduit.

4. An axial fiow compressor as defined in claim 3 having inlet meansconnected with said suction conduit and outlet means connected with saidsecond pressure conduit, said inlet and outlet means being disposedsubstantially in the same radial plane in the middle of the compressor.

FRANZ SCHAER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Number Name Date Collier Oct. 13, 1908Bennett Jan. '7, 1913 Hinsch Dec. 10, 1918 Aue June 28, 1949 FOREIGNPATENTS Country Date Switzerland Oct. 1, 1941

